The present invention relates to a luggage door unlocking device for a vehicle, capable of unlocking the luggage door of a vehicle, particularly, the trunk lid, without using a key.
The luggage door unlocking device of this type comprises a portable signal transmitter for transmitting an unlocking signal comprising a pulse train; a receiver mounted on the vehicle body capable of receiving the unlocking signal transmitted by the portable signal transmitter when the transmitter is close by; and an unlocking means for operating an unlocking mechanism upon the reception of the unlocking signal by the receiver.
The luggage door unlocking device of this type enables the trunk lid to be opened automatically when a person carrying the signal transmitter approaches the trunk lid, thereby eliminating a manual unlocking operation, which is of great convenience in case the person has luggage in both hands.
Generally, the light, electromagnetic wave and ultrasonic wave are possible signaling media in such an unlocking device. The inventors of the present invention took notice of magnetism as a signaling medium or its comparatively satisfactory characteristics unaffected by the noises of the environment. However, it was found through experiments that, in an underground parking lot, the harmonic component of an induction field generated by a burried power cable or the like sometimes overlaps even a magnetic unlocking signal, as a pulse noise of a comparatively short duration. Accordingly, the conventional receiver which receives all the pulse signals of voltage levels above a fixed level as a normal unlocking signal has been likely to cause the erroneous operation of the associated unlocking means.